Prader-Willi Syndrome
(PWS) is an inherited disorder genetic disorder which is generally
caused by a deletion in Chromosome 15. The features of this disorder
includes short stature, mental retardation or learning disabilities,
incomplete sexual development, characteristic behavior problems, and
an insatiable appetite. The syndrome was first described in 1956 by
Drs. Prader, Labhart, and Willi.
The following is an overview of characteristics common to Prader-Willi
Syndrome. However, not all symptoms are present in all individuals
and the intensity of characteristics varies from person to person.
Craniofacial Anomies which include; almond-shaped eyes, narrow-bifrontal
diameter, strabismus and early dental caries/enamel hypoplasia.
Feeding problems in infancy with need for special feeding techniques
and poor weight gain/failure to thrive.
Excessive or rapid weight gain after 12 months of age but before 6
years of age resulting in obesity and an obsession with food.
Developmental delays in a child younger than 6 years of age with mild
to moderate mental retardation or learning problems in older children.
Genital hypoplasia - for males, scrotal hypoplasia, cryptorchidism,
small penis and/or testes for age. For females an absence or severe
hypoplasia of labia minora and/or clitoris.
Sexual maturity not fully developed. The child with PWS will begin
puberty, but not complete it. This results in delayed or incomplete
gonadal maturation with delayed pubertal signs in the absence of intervention
after 16 years of age. In males, small gonads, decreased facial and
body hair, lack of voice change and in females, amenorrhea/oligomenorrhea
after aged 16. This is known as 'precocious puberty' there will be
a development in body hair, some breast development in girls and a
degree of penile development in boys. Menstruation is often scanty
and irregular.
Associated
Features:
Sleep disturbance
or sleep apnoea.
Hypopigmentation - fair skin and hair compared to family.
Eye abnormalities (esotropia, myopia).
Speech articulation defects.
Small hands and/or feet for height age.
Personality Problems.
Differential
Diagnosis:
Some disorders have similar symptoms. The clinician, therefore, in
his diagnostic attempt, has to differentiate against the following
disorders which need to be ruled out to establish a precise diagnosis.
None Identified
Cause:
May be associated
with environmental factors however current research has shown that
the PWS results mainly from one of 4 different genetic abnormalities.
These are:
A small deletion
on chromosome 15.
Chromosome 15
maternal disomy.
A translocation
of chromosomes involving chromosome 15.
An error in
the imprinting of Chromosome 15.
Treatment:
There is no cure for PWS therefore
early diagnosis gives parents an opportunity to manage their child's
diet and avoid obesity and its related problems from the start. However
for children with this disorder it is best to take the multidisciplinary
approach and involve the specialties offered by Pediatrics, Neurology,
Endocrinology, Ophthalmology and Orthopedics.
Counseling
and Psychotherapy [ See
Therapy Section ]:
Most
infants will benefit greatly from these early interventions with a
with appropriate therapists who can help set up a program to encourage
development and provide assistive devices which will help.
